(1) Field of the Invention
The present invention relates to a fabric inspecting method and apparatus for detecting lump type flaws such as soiled spots, strands, knots and swells, and void type flaws such as circular holes, runs and cuts formed on textile and other fabrics.
(2) Description of the Prior Art
Flaws present on textile and other fabrics to be inspected include various types such as the lump type and void type, which makes it difficult to automate the flaw detecting operation. In earlier times, the flaw detection was carried out visually, through the eyes of the worker, while transporting fabrics. The inspection by the human eye did not provide for high efficiency, and was an obstacle to mass production.
A fabric inspecting apparatus for automatically detecting flaws on fabrics is described in "Kako Gijutsu" (or Processing Technology) published in 1983, Vol. 18, No. 11, pages 32 and 33. According to this apparatus, a laser beam emitted from a laser source is turned by a rotating mirror to scan a fabric transversely, and light reflection and transmission from the fabric are detected by two line sensors. Flaws are detected by processing detection signals from the line sensors.
This fabric inspecting system requires the rotating mirror for turning the laser beam to scanning directions, and a drive source for rotating the mirror. This results in a complicated construction, and yet the system is unable to detect lump type flaws present on the back face of the fabric.